Getting the right amount of sleep is crucial for good health and wellbeing, with poor quality sleep being associated with an increased risk of type 2 diabetes, cardiovascular disease, coronary heart disease, mental health conditions, obesity, and death1.
Despite this, over half of Australians report experiencing sleep difficulties– including having trouble falling asleep and staying asleep as well as waking up too early and not being able to get back to sleep – three or more times a week. And nearly half of all Australian adults report regularly experiencing at least 2 sleep-related problems1.
These sleep problems can include:
- Short sleep: getting less sleep than recommended for your age group;
- Long sleep: sleeping longer than recommended for your age group;
- Poor sleep quality, which includes taking too long to fall asleep, waking frequently or for long periods, and poor sleep efficiency;
- Doctor-diagnosed sleep disorders, such as insomnia, restless leg syndrome, or obstructive sleep apnoea
It’s no wonder, then, that patients in Australia are seeking therapeutic and other solutions for their sleep difficulties.
Medicinal cannabis is just one of a number of treatments that are prescribed to treat the symptoms of other sleep disorders like insomnia, restless leg syndrome and more. Let's explore the current research behind medicinal cannabis and sleep
How does medicinal cannabis affect sleep?
Cannabis has been used in numerous cultures for its potential healing properties throughout human history, with the first documented case of its use dating back to 2800 BC3.
Since then, therapeutic indications of cannabis have been mentioned in the texts of the Indian Hindus, Assyrians, Greeks and Romans. All of which report cannabis to relieve pain and treat a vast array of different health problems: including arthritis, depression, amenorrhea, inflammation, lack of appetite, asthma and insomnia.
Today, medicinal cannabis is prescribed to treat a range of chronic health conditions in Australia, the most common being mental health, chronic pain, and sleep conditions4. Some of the sleep conditions medicinal cannabis has been prescribed to treat include:
- Insomnia
- Circadian rhythm disorder
- Sleep movement disorder
- Parasomnia
- Sleep breathing disorder
Medicinal cannabis may also be prescribed to treat sleep issues caused by other chronic conditions, such as chronic pain, anxiety, post-traumatic stress disorder, multiple sclerosis and more. For example, studies have found that medicinal cannabis may have a positive effect on maintaining sleep throughout the night in some chronic pain patients5.
Of the more than 100 phytocannabinoids naturally found within cannabis, THC is most commonly used and prescribed for its ability to induce sleep. This is because THC works directly with the body’s endocannabinoid system, which is responsible for regulating numerous bodily functions, including sleep. THC binds directly with the CB1 receptors in the central nervous system, which can yield an effect on sleep, relaxation, and more6.
Cannabinol, or CBN, is a less well-known cannabinoid which appears to have powerful sedative effects7, which may be enhanced when it’s combined with THC. A number of cannabis terpenes – including caryophyllene, myrcene, linalool, pinene and terpinolene – are also known to have sedating and stress-relieving effects which aid sleep.
The right combination of cannabinoids, terpenes and other cannabis compounds in a strain or type of medicinal cannabis treatment can have a synergistically powerful effect on sleep and other symptoms. This is known as the entourage effect.
In a 2022 study of patients taking medicinal cannabis to improve sleep quality in Canada, it was found that 39% of patients were able to reduce or completely discontinue a prescription medication indicated for sleep, while 71% reported a subjective improvement in their sleep or related condition6.
Does medicinal cannabis affect REM sleep?
When it comes to getting a good night’s sleep, the amount of hours a patient gets makes up only one part of the equation.
Over the course of the night, our entire sleep is made up of several rounds of what is known as the sleep cycle, which has four stages8. On a typical night, a person goes through four to six sleep cycles, which last for approximately 90 minutes each.
The four sleep stages in a sleep cycle include:
Stage 1 (N1)
When you first fall asleep and the body has not fully relaxed. Your body and brain activities start to slow with periods of brief movements. Stage 1 sleep normally lasts just one to seven minutes.
Stage 2 (N2)
When your body enters a more relaxed state, characterised by a drop in temperature, relaxed muscles, slowed breathing and slowed heart rate. Stage 2 sleep can last for 10 to 25 minutes during the first sleep cycle, and each N2 stage can become longer during the night.
Stage 3 (N3, slow-wave, delta or deep sleep)
When your heart rate, breathing rate and body relaxes even further, and your brain produces delta waves. Stage 3 sleep is critical for bodily recovery and growth, as well as immunity and other key bodily functions. You spend the most time in deep sleep during the first half of the night.
Stage 4 (REM sleep)
When your brain activity picks up, nearing levels seen when you are awake. At the same time, your body experiences a temporary paralysis of the muscles, with two exceptions: the eyes and the muscles that control breathing. Even though the eyes are closed, they can be seen moving quickly.
It is believed to be essential to cognitive functions like memory, and it is during this stage that we experience vivid dreams. In total, REM stages make up around 25% of sleep in adults. According to Dr. Melissa Catanzarite (MBBS) ‘REM also preserves memories, which is why a reduction in REM sleep for an extended period of time is associated with early onset cognitive decline, dementia and more. Good sleep now is an investment into the future you.’
Studies have shown that at lower doses, THC can reduce sleep onset latency and contribute to greater ease of falling asleep, increased deep or slow-wave sleep and increased total sleep time. At higher doses, THC-predominant cannabis may cause a reduction in total rapid eye movement sleep and REM density in some patients.
The extent to which cannabis affects REM sleep therefore depends on the dose and frequency the patient consumes cannabis, as well as the amount of THC being consumed.
In one 2008 study, cannabis strains with higher levels of THC were found to suppress the amount of REM sleep participants were getting9. Because it is vital for healthy cognitive and immune functioning, it’s important to consider this effect before taking any cannabinoid treatments for sleep, particularly those high in THC.
A reduction in REM sleep may be beneficial in the short term for patients who would benefit from more time spent in the deep, restorative sleep stage, or for patients who experience PTSD-induced nightmares. More research is needed to understand how cannabis affects sleep cycles over time.
Medicinal cannabis and sleep disorders
Sleep disorders are among the three most common types of conditions4 medicinal cannabis is prescribed to treat in Australia, alongside chronic pain and mental health conditions. Here are some of the conditions medicinal cannabis may be effective at treating:
Medicinal cannabis and insomnia
Insomnia is a sleep disorder characterised by an inability to fall asleep or stay asleep. Insomnia is by far the most common sleep disorder that medicinal cannabis is prescribed to treat in Australia4.
Medicinal cannabis has been found to be well tolerated and to improve insomnia symptoms and sleep quality in some patients with chronic insomnia symptoms9. Medical cannabis treatments for insomnia may also assist patients in discontinuing prescription medications indicated for sleep6. This may appeal to patients experiencing strong or unwanted side effects – such as dizziness, prolonged drowsiness, headaches and more – from their conventional prescription sleeping pills.
Medicinal cannabis and restless leg syndrome
Restless leg syndrome (RLS) is a chronic disorder characterised by an urge to move the legs. This urge is often accompanied by pain or other uncomfortable and unpleasant sensations. RLS may occur or worsen during rest, particularly at night, and temporarily improves with activity. RLS is considered both a sleep disorder and a movement disorder, because the symptoms are triggered by resting and attempting to sleep.
Because RLS is caused by an excessive release of dopamine, medicinal cannabis may be an effective treatment for some patients thanks to its capacity to reduce dopamine synthesis in the body, helping to restore the activity in the basal ganglia to normal levels. The basal ganglia is a part of the brain that uses dopamine to help control muscle activity and movement.
While further medical research and clinical trials are needed, there have been promising patient reports of ‘remarkable and total remission of RLS symptoms' following medical cannabis treatment10.
Medicinal cannabis and narcolepsy
Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. A person with narcolepsy experiences overwhelming daytime drowsiness and, in severe cases, falls asleep involuntarily several times every day.
While there are no clinical studies of medicinal cannabis for the treatment of narcolepsy and related conditions like idiopathic hypersomnia, studies in animals11 suggest they may offer a potential treatment option.
Excessive drowsiness has been shown to be reduced following CBD administration in rats with narcoleptic symptoms, while REM sleep has been shown to be reduced following THC use. This effect is similar to the effect of sodium oxybate, an effective treatment for type 1 narcolepsy. It’s possible then that the combined REM-suppressing effect of THC and the wake-promoting effect of CBD could be harnessed to treat patients with narcolepsy, but more research is needed in this area.
What type of medicinal cannabis is prescribed to treat sleep disorders?
Medicinal cannabis is a highly personalised treatment. What works best for some patients may differ from what works for another patient, even if they share the same condition. When deciding on an appropriate medicinal cannabis treatment to prescribe for sleep disturbances, like insomnia, you should consider:
- The patient’s condition and symptoms
- Individual factors, like the patient’s driving status and medical history
- Available cannabis formats
- Appropriate dosages
- Cannabinoid content and ratios
- Terpene content
- + more
One 2015 study of cannabis for pain relief and sleep found that cannabis strains with equal ratios of THC to CBD had the most positive effect on sleep12. This is partly because CBD may be able to mitigate some of the negative effects associated with higher THC formulations, such as anxiety. Based on available evidence it has been shown that THC used either alone or in combination with CBD have been shown to improve patients perception of sleep13. Medicinal cannabis treatments with sleep-inducing terpenes, such as linalool, myrcene, and caryophyllene, can also be prescribed to promote good sleep hygiene and assist with difficulty sleeping.
The type of medical cannabis prescribed and the method required to take it will depend on the individual needs of the patient. If a patient is experiencing trouble falling asleep, a fast-acting method of consuming their medicinal cannabis treatment – such as inhalation – may be beneficial.
For patients who experience difficulties staying asleep, a longer-lasting medicinal cannabis treatment, such as oil, wafer, or tincture, may work best for you. For some patients, a combination of both may work best.
Which medical cannabis strain is best for inducing sleep?
Although indica-dominant strains have historically been associated with relaxing, sedating effects, today’s research suggests that the cannabinoid ratio (i.e. the ratio of THC to CBD) and terpene content has a greater influence on its effects on the user or patient.
Potential risks and side effects of using medicinal cannabis as a sleeping aid
Like any medication, medical cannabis can come with its own risks and side effects which will vary depending on the type and amount of treatment, and individual factors like tolerance, endocannabinoid system function, and sensitivity.
Some of the potential risks and side effects associated with using medical cannabis as a sleep aid include:
- High doses of THC may impact the sleep cycle by suppressing REM sleep
- High doses of THC or consuming too late in the night can also lead to feeling groggy or tired the next day
- While THC has the potential to reduce anxiety symptoms, THC may also cause or increase anxiety when taken at too high a dose in some patients
When it comes to starting any medical cannabis treatment, working with your patient to find the right dosing and titration is key to maximising the therapeutic benefit of their medication while mitigating the potential risks and side effects.
